Semiconductor manufacturing apparatus and method of manufacturing semiconductor device

ABSTRACT

A method of manufacturing a semiconductor device includes placing a substrate in a housing, supplying first gas containing molybdenum to the housing to form a film that contains molybdenum, on the substrate, removing the substrate with the formed film from the hosing, and then supplying second gas containing chlorine to the housing to remove molybdenum deposited on a surface of the housing.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2019-020713, filed Feb. 7, 2019, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a semiconductormanufacturing apparatus and a method of manufacturing a semiconductordevice.

BACKGROUND

Using molybdenum to form a metal layer over a substrate may causedeposition of molybdenum on an integral part of a semiconductormanufacturing apparatus, such as an inner wall of the semiconductormanufacturing apparatus and a component in the semiconductormanufacturing apparatus. The deposited molybdenum may cause depositionof particles on the substrate.

DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a structure of a semiconductormanufacturing apparatus according to a first embodiment.

FIGS. 2-11 illustrate cross-sectional views of a structure to illustratea method of manufacturing a semiconductor device according to the firstembodiment in this order.

FIG. 12 is a graph to explain the method of manufacturing thesemiconductor device according to the first embodiment.

FIG. 13 is another graph to explain the method of manufacturing thesemiconductor device according to the first embodiment.

FIG. 14 schematically illustrates a structure of a semiconductormanufacturing apparatus according to a second embodiment.

DETAILED DESCRIPTION

Embodiments provide a semiconductor manufacturing apparatus directed tosolving a problem due to deposition of molybdenum and also provide amethod of manufacturing a semiconductor device.

In general, according to an embodiment, a method of manufacturing asemiconductor device includes placing a substrate in a housing,supplying first gas containing molybdenum to the housing to form a filmthat contains molybdenum, on the substrate, removing the substrate withthe formed film from the hosing, and then supplying second gascontaining chlorine to the housing to remove molybdenum deposited on asurface of the housing.

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings. In FIGS. 1 to 14, the same or similarcomponents are denoted by the same symbols, and the same explanation isnot repeated.

First Embodiment

FIG. 1 schematically illustrates a structure of a semiconductormanufacturing apparatus according to a first embodiment. Thesemiconductor manufacturing apparatus illustrated in FIG. 1 is, forexample, a single-wafer chemical vapor deposition (CVD) apparatus.

The semiconductor manufacturing apparatus illustrated in FIG. 1 includesa CVD chamber 11, a wafer stage 12, a showerhead 13, a gas introductionpiping 14, multiple gas supply sources 15, multiple mass flowcontrollers (MFCs) 16, a radio frequency (RF) power source 17, a gasdischarge piping 18, and a controller 19. The CVD chamber 11 is anexample of a housing.

The CVD chamber 11, the wafer stage 12, and the showerhead 13 haveheaters 11 a, 12 a, and 13 a, respectively. The multiple gas supplysources 15 include gas supply sources 15 a and 15 b for film depositiongas and gas supply sources 15 c and 15 d for cleaning gas. The multipleMFCs 16 include MFCs 16 a and 16 b for the film deposition gas and MFCs16 c and 16 d for the cleaning gas. Among these gas supply sources 15and the MFCs 16, the gas supply source 15 a and the MFC 16 a areexamples that make up a first gas supply section, and the gas supplysource 15 c and the MFC 16 c are examples that make up a second gassupply section.

The CVD chamber 11 houses a wafer W as a substrate. The wafer stage 12supports and rotates the wafer W in the CVD chamber 11. The heater 11 ais used to heat an inner wall of the CVD chamber 11 and a space in theCVD chamber 11. The inner wall of the CVD chamber 11 is an example of astructural member of the housing. The heater 11 a may also function toheat the gas discharge piping 18. The heater 12 a is used to heat thewafer stage 12 itself and the wafer W on the wafer stage 12. The waferstage 12 is an example of a component in the housing.

FIG. 1 illustrates an X direction and a Y direction that are parallel toa surface of the wafer W and that are mutually perpendicular and alsoillustrates a Z direction that is perpendicular to the surface of thewafer W. In this specification, +Z direction is assumed as an upperdirection, whereas −Z direction is assumed as a lower direction. The −Zdirection may or may not be the gravity direction.

The showerhead 13 is provided in the CVD chamber 11 and supplies gasfrom the gas introduction piping 14 to the CVD chamber 11. The waferstage 12 and the showerhead 13 also respectively function as lowerelectrode and upper electrode that apply voltage to the gas in the CVDchamber 11. The heater 13 a is used to heat the showerhead 13. Theshowerhead 13 is an example of the component in the housing.

The gas supply sources 15 a and 15 b supply the film deposition gas tothe CVD chamber 11 via the gas introduction piping 14. Specifically, thegas supply source 15 a supplies a first gas containing molybdenum, forexample, MoF₆ gas, MoCl₅ gas, or Mo(CO)₆ gas. The symbols Mo, F, Cl, C,and O respectively denote molybdenum, chlorine, fluorine, carbon, andoxygen. The gas supply source 15 b supplies other gas, for example, H₂gas. The symbol H denotes hydrogen. Each of the gas supply sources 15 aand 15 b includes, for example, a gas tank and a unit related to the gastank.

When the gas supply sources 15 a and 15 b supply MoF₆ gas and H₂ gas tothe CVD chamber 11, MoF₆ gas and H₂ gas react with each other, therebyforming a Mo film over the wafer W as a metal layer. At this time, theMo film is deposited on a surface of the inner wall of the CVD chamber11 and surfaces of the components in the CVD chamber 11, such as of thewafer stage 12 and of the showerhead 13. Moreover, when residues andreaction products of these gas are discharged from the CVD chamber 11 tothe gas discharge piping 18, the Mo film is also deposited on a surfaceof the gas discharge piping 18.

The gas supply sources 15 c and 15 d supply the cleaning gas to the CVDchamber 11 via the gas introduction piping 14. Specifically, the gassupply source 15 c supplies a second gas containing chlorine, forexample, Cl₂ gas. The vapor pressure of the second gas is desirably 10torr or higher at 150° C. The second gas may be HCl gas. The gas supplysource 15 d supplies other gas, for example, at least either one of H₂gas and O₂ gas. Each of the gas supply sources 15 c and 15 d includes,for example, a gas tank and a unit related to the gas tank. The gassupply sources 15 b and 15 d may have respective gas sources as H₂ gassources or may have a common gas source as the H₂ gas source.

After the wafer W with the formed Mo film is taken out of the CVDchamber 11, the gas supply sources 15 c and 15 d supply a mixed gascontaining Cl₂ gas and at least either one of H₂ gas and O₂ gas to theCVD chamber 11. As a result, the Mo film deposited on the inner wall ofthe CVD chamber 11 and other components reacts with the Cl₂ gas to formmolybdenum chloride, thereby being removed from the inner wall of theCVD chamber and other components. Thus, the semiconductor manufacturingapparatus of the first embodiment is cleaned. In addition, when residuesand reaction products of these gas are discharged from the CVD chamber11 to the gas discharge piping 18, the Mo film is also removed from thesurface of the gas discharge piping 18.

Adding H₂ gas to the Cl₂ gas accelerates the reaction between the Mofilm and the Cl₂ gas. The ratio or the partial pressure ratio of the H₂gas in the mixed gas is desirably less than or equal to 1%. Adding O₂gas to the Cl₂ gas increases vapor pressure of the reaction product ofthe reaction between the Mo film and the Cl₂ gas. The ratio or thepartial pressure ratio of the O₂ gas in the mixed gas is desirably lessthan or equal to 50%. Details of these H₂ gas and O₂ gas will bedescribed later.

The MFCs 16 a to 16 d control flow rates of gases from the gas supplysources 15 a to 15 d, respectively. This enables controlling the flowrates of these gas and the pressures in the CVD chamber 11 of these gas.The MFCs 16 a to 16 d desirably have structures suitable for the typesof the gases from the gas supply sources 15 a to 15 d, respectively. Forexample, the MFC 16 c receives Cl₂ gas from the gas supply source 15 c,and therefore, the MFC 16 c and piping therearound are desirably made ofmaterials with resistance to Cl₂ gas.

The RF power source 17 applies high-frequency power between the lowerelectrode and the upper electrode, that is, between the wafer stage 12and the showerhead 13. Thus, voltage is applied to the gas in the CVDchamber 11. For example, applying the voltage to the mixed gas at thetime of cleaning the semiconductor manufacturing apparatus acceleratesthe reaction between the Mo film and the Cl₂ gas.

The gas discharge piping 18 is used to discharge the gas from the CVDchamber 11. As described above, the gas discharge piping 18 is used, forexample, after the Mo film is formed over the wafer W and after thesemiconductor manufacturing apparatus is cleaned.

The controller 19 controls various operations of the semiconductormanufacturing apparatus. An example of the controller 19 includes aprocessor, an electric circuit, and a personal computer (PC). Thecontroller 19 controls, for example, carrying the wafer W into the CVDchamber 11, carrying the wafer W out from the CVD chamber 11, elevatingand rotating the wafer stage 12, supplying gases from the gas supplysources 15, operations of the MFCs 16, and operation of the RF powersource 17.

The controller 19 also controls operations of the heaters 11 a, 12 a,and 13 a at the time of cleaning the semiconductor manufacturingapparatus. Specifically, the controller 19 controls the heaters 11 a, 12a, and 13 a to heat the inner wall of the CVD chamber 11, the space inthe CVD chamber 11, the wafer stage 12, the showerhead 13, and the gasdischarge piping 18 to 50° C. or higher. This can prevent re-depositionof molybdenum chloride on the inner wall of the CVD chamber 11 and othercomponents. Details of these beatings will be described later.

FIGS. 2 to 11 are cross-sectional views of a structure to illustrate amethod of manufacturing a semiconductor device according to the firstembodiment in this order. The semiconductor device of the firstembodiment is, for example, a three-dimensional semiconductor memory,and the semiconductor device is manufactured by the semiconductormanufacturing apparatus illustrated in FIG. 1.

First, a diffusion layer 101 that is connected to a select transistor isformed in the substrate 100, an interlayer insulating film 102 is formedon the substrate 100, and multiple sacrifice layers 103 and multipleinsulating layers 104 are stacked alternately on the interlayerinsulating film 102, as illustrated in FIG. 2. The substrate 100 is, forexample, a semiconductor substrate, such as a silicon (Si) substrate,and the substrate 100 corresponds to the wafer W. The interlayerinsulating film 102 is, for example, a SiO₂ film. The sacrifice layer103 is, for example, a SiN film formed by CVD, which has a filmthickness of 30 nm. The symbol N denotes nitrogen. The number of thesacrifice layers 103 is, for example, 24. The insulating layer 104 is,for example, a SiO₂ film formed by CVD, which has a film thickness of 30nm. The number of the insulating layers 104 is, for example, 24. Thesacrifice layers 103 and the insulating layers 104 are used to formmemory cells. The sacrifice layer 103 and the insulating layer 104 areexamples of first and second layers, respectively.

Next, a memory hole 105 is formed in the sacrifice layers 103 and theinsulating layers 104, as illustrated in FIG. 3. For example, the memoryhole 105 has a diameter of 80 nm and is formed by lithography.

Then, a block insulating film 106, a charge storing layer 107, a tunnelinsulating film 108, a channel semiconductor layer 109, and a sidewallinsulating film 110 are formed in this order from the surfaces of thesacrifice layers 103 and the insulating layers 104 inside the memoryhole 105, as illustrated in FIG. 4. The block insulating film 106 is,for example, an aluminum oxide (Al₂O₃) film with a film thickness of 15nm, which is formed by using trimethylaluminum (TMA) and O₃. The chargestoring layer 107 is, for example, a SiN film with a film thickness of 5nm, which is formed by using tris(dimethylamido)silane (3DMAS) and NH₃.The tunnel insulating film 108 is, for example, a SiO₂ film with a filmthickness of 8 nm, which is formed by using 3DMAS and O₃. The blockinsulating film 106, the charge storing layer 107, and the tunnelinsulating film 108 are formed by atomic layer deposition (ALD), forexample. The channel semiconductor layer 109 is, for example, apolysilicon layer with a film thickness of 5 nm. The sidewall insulatingfilm 110 is, for example, a SiO₂ film with a film thickness of 5 nm.

Next, a contact hole 111 is formed by reactive ion etching (RIE) usingthe sidewall insulating film 110 as a mask so as to penetrate throughthe sidewall insulating film 110, the channel semiconductor layer 109,the tunnel insulating film 108, and the charge storing layer 107, theblock insulating film 106, and the interlayer insulating film 102, asillustrated in FIG. 5. This makes the diffusion layer 101 be exposed inthe contact hole 111.

Thereafter, the sidewall insulating film 110 is removed by selectiveRIE, and a semiconductor layer 112 is further formed on the surfaces ofthe channel semiconductor layer 109, the tunnel insulating film 108, thecharge storing layer 107, the block insulating film 106, the interlayerinsulating film 102, and the diffusion layer 101 in the memory hole 105and in the contact hole 111, as illustrated in FIG. 6. The semiconductorlayer 112 is, for example, a polysilicon layer with a film thickness of5 nm, which is formed so as to completely fill the contact hole 111. Thesemiconductor layer 112 in the contact hole 111 functions as a contactplug, and the semiconductor layer 112 in the memory hole 105 functionsas a channel together with the channel semiconductor layer 109.

Then, a core insulating film 113 is formed on a surface of thesemiconductor layer 112 in the memory hole 105, as illustrated in FIG.7. The core insulating film 113 is, for example, a SiO₂ film, which isformed so as to completely fill the memory hole 105.

Thereafter, a slit 114 is formed in the sacrifice layers 103 and in theinsulating layers 104 by lithography and RIE, as illustrated in FIG. 8.

The sacrifice layers 103 are removed through the slit 114 by wet etchingusing phosphoric acid that is heated to 150° C., as illustrated in FIG.9. As a result, holes 115 are formed between the insulating layers 104.

Next, a barrier metal layer 116 and an electrode material layer 117 areformed in this order from the surfaces of the block insulating film 106,the insulating layers 104, and the interlayer insulating film 102 in theslit 114 and in the hole 115, as illustrated in FIG. 10. The barriermetal layer 116 is, for example, a metal layer containing titanium (Ti)or tantalum (Ta). The electrode material layer 117 is, for example, a Mofilm, which is formed in the CVD chamber 11 as illustrated in FIG. 1 byusing MoF₆ gas and H₂ gas from the gas supply sources 15 a and 15 b. Theelectrode material layer 117 is formed so as to have a film thickness of30 nm, at 450° C., for example.

Then, redundant parts of the barrier metal layer 116 and the electrodematerial layer 117 in the slit 114 are removed, and an insulating film118 is formed in the slit 114, as illustrated in FIG. 11. The insulatingfilm 118 is, for example, a SiO₂ film, which is formed so as tocompletely fill the slit 114. After these processes, multiple memorycells are formed having a MONOS structure including the electrodematerial layer 117 and the barrier metal layer 116, the block insulatingfilm 106, the charge storing layer 107, the tunnel insulating film 108,and the channel semiconductor layer 109 and the semiconductor layer 112.

Thereafter, various kinds of wiring layers and interlayer insulatinglayers are formed over the substrate 100. Thus, the semiconductor deviceof the present embodiment is manufactured.

In forming the electrode material layer 117 by using H₂ gas, C₂H₂ gas orSiH₄ gas may also be simultaneously supplied in addition to the H₂ gas.In addition, in forming the electrode material layer 117, MoCl₅ gas orMo(CO)₆ gas may be supplied instead of MoF₆ gas.

The following describes details of the electrode material layer 117 ofthe present embodiment.

In order to improve a degree of integration of a three-dimensionalsemiconductor memory, for example, the electrode material layer 117 mustbe thinned. However, thinning the electrode material layer 117 causesincrease in the resistance of the electrode material layer 117.

In view of this, the present embodiment uses a Mo film for the electrodematerial layer 117. This enables keeping the resistance of the electrodematerial layer 117 low even though the electrode material layer 117 isthinned. However, in the case of making the electrode material layer 117so as to be formed of the Mo film, when the electrode material layer 117is formed, the Mo film tends to be deposited on the inner wall of theCVD chamber 11 and other components. The deposited Mo film may come offlater, which may cause deposition of particles on the substrate 100.

From this point of view, in the present embodiment, after the substrate100 that has the electrode material layer 117 formed thereover is takenout from the CVD chamber 11, the semiconductor manufacturing apparatusis cleaned by the method as described above. The following describesdetails of cleaning of the semiconductor manufacturing apparatus.

In order to clean the semiconductor manufacturing apparatus of thepresent embodiment, Cl₂ gas is supplied from the gas supply source 15 cto the CVD chamber 11. In the present embodiment, to accelerate reactionbetween the deposited Mo film and the Cl₂ gas, the RF power source 17applies high-frequency power of 100 to 1000 W to the showerhead 13. As aresult, the deposited Mo film reacts with the Cl₂ gas to form gas ofmolybdenum chloride, in the CVD chamber 11.

In the present embodiment, to prevent molybdenum chloride from beingdeposited on the inner wall of the CVD chamber 11 and other components,the inner wall of the CVD chamber 11, the space in the CVD chamber 11,the wafer stage 12, the showerhead 13, and the gas discharge piping 18are heated to 50° C. or higher during cleaning the semiconductormanufacturing apparatus. This increases vapor pressure of molybdenumchloride and makes molybdenum chloride less likely to be re-deposited onthe inner wall of the CVD chamber 11 and other components.

For example, the inner wall of the CVD chamber 11 and the space in theCVD chamber 11 are heated to 50 to 100° C. by the heater 11 a. The waferstage 12 is heated to 300 to 500° C. by the heater 12 a. The showerhead13 is heated to 50 to 100° C. by the heater 13 a. The gas dischargepiping 18 is heated to 50 to 100° C. by the heater 11 a. The operationsof the heaters 11 a, 12 a, and 13 a are controlled by the controller 19.The temperature of the substrate 100 in forming the electrode materiallayer 117 over the substrate 100 is set to, for example, approximately600° C. by the heater 12 a.

The present embodiment uses Cl₂ gas for removing the deposited Mo film.This Cl₂ gas is an example of the second gas. Gas that containschlorine, such as Cl₂ gas, generally has a high vapor pressure. Thisprovides advantageous effects, that is, the Mo film is easily removed,and Mo once removed is less likely to be deposited on the inner wall ofthe CVD chamber 11 and other components. In the present embodiment, gaswith a vapor pressure of 10 torr or higher at 150° C. is desirably usedas the gas containing chlorine. In the present embodiment, the flow rateof the Cl₂ gas is adjusted to 50 sccm, and the pressure of the Cl₂ gasin the CVD chamber 11 is adjusted to 1 torr. While the second gas of thepresent embodiment contains chlorine, the first gas of the presentembodiment may contain chlorine as in the case of MoCl₅ gas, or it isnot necessary that the first gas contains chlorine, as in the cases ofMoF₆ gas and Mo(CO)₆ gas.

In cleaning the semiconductor manufacturing apparatus of the presentembodiment, a mixed gas containing Cl₂ gas and H₂ gas may be supplied tothe CVD chamber 11. This enables accelerating the reaction between theMo film and the Cl₂ gas. An excessive amount of H₂ gas may causereaction between H₂ gas and the Mo film and reaction between H₂ gas andO₂ gas. In consideration of this problem, the ratio of the H₂ gas in themixed gas is desirably less than or equal to 1%.

In cleaning the semiconductor manufacturing apparatus of the presentembodiment, a mixed gas containing Cl₂ gas and O₂ gas may be supplied tothe CVD chamber 11. This enables increasing vapor pressure of a productof the reaction between the Mo film and the Cl₂ gas. An excessive amountof H₂ gas may cause generation of molybdenum oxide, and therefore, theratio of the O₂ gas in the mixed gas is desirably less than or equal to50%.

The semiconductor manufacturing apparatus of the present embodiment maybe cleaned at each time of processing one wafer W or at each time ofprocessing multiple wafers W.

FIG. 12 is a graph to explain the method of manufacturing thesemiconductor device according to the first embodiment.

FIG. 12 illustrates a vapor pressure curve of MoCl₅. The vapor pressureof MoCl₅ is approximately 5 torr at around 50° C. and is approximately10 torr at 80° C.

As described above, the gas of molybdenum chloride may be re-depositedon the inner wall of the CVD chamber 11 and other components. Toeffectively prevent this re-deposition, the vapor pressure of the gas ofmolybdenum chloride is desirably made to be higher than a degree of 2 to3 torr, and for example, it is desirably 5 torr or higher.

In the case in which the molybdenum chloride is MoCl₅, the vaporpressure of the molybdenum chloride is 5 torr or higher by making themolybdenum chloride have a temperature of 50° C. or higher. Othermolybdenum chlorides also have a vapor pressure close to that of MoCl₅.In view of this, the temperatures of the inner wall of the CVD chamber11 and other components are set to be 50° C. or higher during clearing,in the first embodiment.

FIG. 13 is another graph to explain the method of manufacturing thesemiconductor device according to the first embodiment.

FIG. 13 illustrates temperature dependencies of various kinds ofmolybdenum chlorides, a molybdenum oxide, and a molybdate compound. Asillustrated in FIG. 13, the vapor pressure of MoO₂Cl₂ is high, whereasthe vapor pressure of MoO₂ is low.

As described above, in cleaning the semiconductor manufacturingapparatus of the first embodiment, the mixed gas containing Cl₂ gas andO₂ gas may be supplied to the CVD chamber 11. At this time, compoundssuch as MoO₂Cl₂ may be generated if the supply amount of O₂ is small,whereas compounds such as MoO₂ may be generated if the supply amount ofO₂ is great. In the former case, re-deposition of Mo hardly occurs dueto a high vapor pressure of MoO₂Cl₂. On the other hand, in the lattercase, re-deposition of Mo tends to occur due to low vapor pressure ofMoO₂. Thus, the ratio of the O₂ gas in the mixed gas is desirably notvery high, and for example, it is desirably less than or equal to 50%.

As described above, the semiconductor manufacturing apparatus of thefirst embodiment is cleaned by using the gas containing chlorine afterthe Mo film is formed over the wafer W. This enables forming a lowresistant Mo film as the metal layer of the semiconductor device andalso enables preventing deposition of particles on the wafer W due tothe Mo film.

More details of the advantageous effects of cleaning in the firstembodiment are described below.

The first embodiment uses the Mo films as the multiple electrodematerial layers 117 that are stacked on the multiple insulating layers104 in an alternating manner over the substrate 100. This enableskeeping the resistance of the electrode material layer 117 low eventhough the electrode material layer 117 is thinned for improving thedegree of integration of the semiconductor device. However, if the Mofilm deposited on the semiconductor manufacturing apparatus is left asit is, particles may be deposited on the substrate 100, therebydecreasing the yield of the semiconductor device.

In consideration of this, cleaning is performed to remove the Mo filmdeposited on the semiconductor manufacturing apparatus, in the firstembodiment. At this time, the gas that is produced by the reaction ofthe Mo film, that is, the reaction product gas, desirably has a highvapor pressure in order to prevent re-deposition of Mo.

The reaction product gas partially remains in the CVD chamber 11 afterthe Mo film is removed. This reaction product gas may generateimpurities, which may be deposited on the substrate 100 in forming theMo film over a next substrate 100. Thus, the reaction product gas isdesirably composed of elements that have a little negative effect on thesubstrate 100 when deposited on the next substrate 100.

For this reason, the first embodiment uses a chlorine-containing gas,such as Cl₂ gas or HCl gas, for removing the Mo film. Chlorine enablespreventing re-deposition of Mo by generating a reaction product gas witha high vapor pressure, such as MoCl₅, and also enables avoiding thenegative effect of the impurities because chlorine generally does notgreatly degrade the memory cell at 600° C. or less.

In addition, a compound of molybdenum and chlorine generally does nothave a sufficient vapor pressure at room temperatures, but this compoundsufficiently evaporates as gas at 50° C. or higher. Thus, in the case ofusing the chlorine-containing gas for removing the Mo film, thesemiconductor manufacturing apparatus is heated to 50° C. or higher.This enables effectively removing the deposited Mo film and effectivelypreventing re-deposition of Mo. These advantageous effects can befurther increased by adding O₂ gas or H₂ gas to the chlorine-containinggas.

As described above, the first embodiment enables effectively preventingthe problem caused by molybdenum deposited on the semiconductormanufacturing apparatus.

Second Embodiment

FIG. 14 schematically illustrates a structure of a semiconductormanufacturing apparatus according to a second embodiment. Thesemiconductor manufacturing apparatus illustrated in FIG. 14 is, forexample, a batch CVD apparatus.

The semiconductor manufacturing apparatus illustrated in FIG. 14includes a CVD furnace 21, a wafer support fixture 22, a gasintroduction piping 23, multiple gas supply sources 24, multiple MFCs25, a gas discharge piping 26, and a controller 27. The CVD furnace 21is an example of the housing.

The CVD furnace 21 has a heater 21 a. The multiple gas supply sources 24include gas supply sources 24 a and 24 b for the film deposition gas andgas supply sources 24 c and 24 d for the cleaning gas. The multiple MFCs25 include MFCs 25 a and 25 b for the film deposition gas and MFCs 25 cand 25 d for the cleaning gas. Among these gas supply sources 24 and theMFCs 25, the gas supply source 24 a and the MFC 25 a are examples thatmake up the first gas supply section, and the gas supply source 24 c andthe MFC 25 c are examples that make up the second gas supply section.

The CVD furnace 21 houses multiple wafers W as substrates. The wafersupport fixture 22 supports and rotates these wafers W in the CVDfurnace 21. The heater 21 a is used to heat an inner wall of the CVDfurnace 21, a space in the CVD furnace 21, and the wafers W. The innerwall of the CVD furnace 21 is an example of the structural member of thehousing. The heater 21 a may also function to heat the gas dischargepiping 26.

The structures and functions of the gas introduction piping 23, the gassupply sources 24, the MFCs 25, the gas discharge piping 26, and thecontroller 27 are respectively similar to the structures and functionsof the gas introduction piping 14, the gas supply sources 15, the MFCs16, the gas discharge piping 18, and the controller 19 in FIG. 1. Thecontroller 27 controls, for example, carrying the wafers W into the CVDfurnace 21, carrying the wafers W out from the CVD furnace 21, rotatingthe wafer support fixture 22, supplying gases from the gas supplysources 24, and operations of the MFCs 25.

The controller 27 also controls operation of the heater 21 a at the timeof cleaning the semiconductor manufacturing apparatus. Specifically, thecontroller 27 controls the heater 21 a to heat the space in the CVDfurnace 21 to 300 to 500° C. This enables preventing re-deposition ofmolybdenum chloride on the inner wall of the CVD furnace 21 and othercomponents.

The types of the gases that are supplied from the gas supply sources 24a to 24 d are similar to those of the gases that are supplied from thegas supply sources 15 a to 15 d in FIG. 1. The gas supply source 24 csupplies, for example, Cl₂ gas or HCl gas. The gas supply source 24 dsupplies, for example, at least either one of H₂ gas and O₂ gas. Thegases from the gas supply sources 24 a to 24 d are supplied to the CVDfurnace 21 via the MFCs 25 a to 25 d, respectively. In cleaning in thesecond embodiment, for example, the flow rate of HCl gas is adjusted to200 sccm, and the pressure of HCl gas in the CVD furnace 21 is adjustedto 20 torr. The method of manufacturing the semiconductor deviceillustrated in FIGS. 2 to 11 may be implemented by using thesemiconductor manufacturing apparatus of the second embodiment.

As in the case of the first embodiment, the second embodiment enableseffectively preventing the problem caused by molybdenum deposited on thesemiconductor manufacturing apparatus.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A method of manufacturing a semiconductor devicecomprising: placing a substrate in a housing; supplying first gascontaining molybdenum to the housing to form a film that containsmolybdenum, on the substrate; removing the substrate with the formedfilm from the hosing; and after the substrate with the formed film isremoved from the hosing, supplying second gas containing chlorine to thehousing to remove molybdenum deposited on a surface of the housing. 2.The method according to claim 1, wherein the second gas has a vaporpressure of 10 torr or higher at 150° C.
 3. The method according toclaim 1, wherein the second gas contains Cl₂ gas or HCl gas.
 4. Themethod according to claim 1, wherein said supplying the second gascomprises supplying mixed gas containing the second gas and at least oneof H₂ gas and O₂ gas to the housing.
 5. The method according to claim 4,wherein the mixed gas contain the O₂ gas, and a ratio of the O₂ gas inthe mixed gas is less than or equal to 50%.
 6. The method according toclaim 4, wherein the mixed gas contain the H₂ gas, and a ratio of the H₂gas in the mixed gas is less than or equal to 1%.
 7. The methodaccording to claim 1, further comprising: heating at least one of astructural member of the housing, a space in the housing, a component inthe housing, and piping for discharging gas from the housing, to 50° C.or higher while the second gas is supplied to the housing.
 8. The methodaccording to claim 1, further comprising: forming multiple first layersand multiple second layers alternately on the substrate; and formingmultiple holes between the second layers by removing the first layers;wherein the film is formed in each of the multiple holes.
 9. The methodaccording to claim 1, wherein said placing the substrate in the housingcomprises placing the substrate on a stage, said supplying the first gascomprises supplying the first gas through a shower head that is providedin the housing and faces the stage, and said supplying the second gascomprises supplying the second gas through the shower head.
 10. Themethod according to claim 1, wherein said placing the substrate in thehousing comprises placing a plurality of substrates set in a rackstructure in the housing, and the substrate is one of the plurality ofsubstrates.
 11. A semiconductor manufacturing apparatus comprising: ahousing; a first gas supply section configured to supply first gascontaining molybdenum; a second gas supply section configured to supplysecond gas containing chlorine; and a controller configured to: causethe first gas to be supplied to the housing from the first gas supplysection when a substrate is placed in the housing, such that a filmcontaining molybdenum is formed on the substrate; and cause the secondgas to be supplied to the housing from the second gas supply sectionafter the substrate with the film is removed from the housing, such thatmolybdenum deposited on a surface of the housing is removed.
 12. Thesemiconductor manufacturing apparatus according to claim 11, wherein thesecond gas has a vapor pressure of 10 torr or higher at 150° C.
 13. Thesemiconductor manufacturing apparatus according to claim 11, wherein thesecond gas contains Cl₂ gas or HCl gas.
 14. The semiconductormanufacturing apparatus according to claim 11, wherein the second gassupply section is configured to supply mixed gas containing the secondgas and at least one of H₂ gas and O₂ gas to the housing.
 15. Thesemiconductor manufacturing apparatus according to claim 14, wherein themixed gas contain the O₂ gas, and a ratio of the O₂ gas in the mixed gasis less than or equal to 50%.
 16. The semiconductor manufacturingapparatus according to claim 14, wherein the mixed gas contain the H₂gas, and a ratio of the H₂ gas in the mixed gas is less than or equal to1%.
 17. The semiconductor manufacturing apparatus according to claim 11,further comprising: a heater configured to heat at least one of astructural member of the housing, a space in the housing, a component inthe housing, and piping for discharging gas from the housing, whereinthe controller is further configured to control the heater to heat atleast one of the member, the space, the component, and the piping to 50°C. or higher when the second gas is supplied to the housing.
 18. Thesemiconductor manufacturing apparatus according to claim 11, wherein thesecond gas supply section includes a flow rate controller configured tocontrol a flow rate of the second gas.